#include<bits/stdc++.h>
using namespace std;
int m[100000010];
int min(int a , int b , int c){
	int min = 12345678;
	if(a < min){
		min = a;
	}
	if(b < min){
		min = b;
	}
	if(c < min){
		min = c;
	}
	return min;
}
int f(int n) {
	if (m[n] > 0) return m[n];
	
	if (n >= 11) {
		m[n] = min(f(n-1), f(n-5), f(n-11)) + 1;
	} else if(n >= 5) {
		m[n] = min(f(n-1), f(n-5)) + 1;
	} else {
		m[n] = n;
	}
	return m[n];
}
int main(){
	int n;
	cin >> n;
	f(n);
	cout << m[n] << endl;
	return 0;
}
